[Guest]

You are training for a local marathon. You want to run the marathon at an average speed of six miles per hour. Unfortunately, you realize you are not in as good shape as you thought and you are running uphill. You find that you complete a half of the run, all uphill, at an average speed of only three miles per hour.

How fast must you run to make the return trip (all downhill) at an average speed for the entire round trip of six miles per hour?

[preflop]

You can't do it, or more precisely you need to run the next half in zero seconds to average at 6 mph.

[Guest]

9 mph

[Guest]

Fun puzzle.

You would have to run infinitely fast.

rate = distance / time

time = distance / rate

If the race is 26 miles, and you ran 13 miles at 3 mph, then it took you 4 1/3 hours.

To run the 26 miles at a rate of 6 mph, it must take you a total of 4 1/3 hours.

Therefore you must finish the last 13 miles in no time, and must run infinitely fast.

[Guest]

Lets say this is a true 26.2 mile marathon. you run 13.1 miles at 3 Mph it takes you 4.366 hours. If you divide 26.2 by 6 Mph you get 4.366 hours.

No matter the distances you use it can not be done.

Stupid math and it's rules

[Guest]

You are training for a local marathon. You want to run the marathon at an average speed of six miles per hour. Unfortunately, you realize you are not in as good shape as you thought and you are running uphill. You find that you complete a half of the run, all uphill, at an average speed of only three miles per hour.

How fast must you run to make the return trip (all downhill) at an average speed for the entire round trip of six miles per hour?

You must

Into a wormhole and return in 0 seconds, as you've already expended the 4.367 hours you would have to finish in in order to average 6 MPH

[Guest]

You all need to read the riddle. It mentions nothing about completing it in a certain amount of time. It says half is uphill half is downhill. They want to "average 6 mph" and average is the sum of all numbers divided by the amount of numbers added. They ran half of it uphill for 3 mph. The rest is downhill if they want to average 6 mph for the whole marathon they must finish the rest of the marathon running 9 mph to average the 6 because 3+9=12. You take that 12 and divide it by 2 and you will get your 6mph. I think it wasn't meant to be as complicated as many are putting it out to be.

[Guest]

You all need to read the riddle. It mentions nothing about completing it in a certain amount of time. It says half is uphill half is downhill. They want to "average 6 mph" and average is the sum of all numbers divided by the amount of numbers added. They ran half of it uphill for 3 mph. The rest is downhill if they want to average 6 mph for the whole marathon they must finish the rest of the marathon running 9 mph to average the 6 because 3+9=12. You take that 12 and divide it by 2 and you will get your 6mph. I think it wasn't meant to be as complicated as many are putting it out to be.

I may be wrong here as well the more i re-read the riddle.

[Guest]

if you run 3mph for 1 hour you run 3 miles

if you run 9mph for 1 hour you run 9 miles

3+9=12 miles @ 2 hours or 6mph

But here is the problem, if the first half is only 3 miles then the total lenght is 6 miles.

[Guest]

if you run 3mph for 1 hour you run 3 miles

if you run 9mph for 1 hour you run 9 miles

3+9=12 miles @ 2 hours or 6mph

But here is the problem, if the first half is only 3 miles then the total lenght is 6 miles.

A marathon is 26 miles.

[Guest]

This was one of my favorites...

those who answered that it's impossible are correct. You can't average speed and distance. put an arbitrary distance to it and you realize you have used up all your time in the first half.

[Guest]

Actually its 26.2. It was easier to use 6 miles to demonstrate the problem. If you look at my answer earlier you would see I used 26.2.

[Guest]

You can't average 6 miles per hour for the marathon even if you drove down the hill.

At 3mph over the course of 13.1 miles it would take 4 hours and 22 minutes. In order to

complete the marathon at a rate of 6 miles per hour you would have to finish the

entire 26.2 miles in a time of 4 hours and 22 minutes, leaving exactly no time remaining

to finish the second half of the race.

[Guest]

You are training for a local marathon. You want to run the marathon at an average speed of six miles per hour. Unfortunately, you realize you are not in as good shape as you thought and you are running uphill. You find that you complete a half of the run, all uphill, at an average speed of only three miles per hour.

How fast must you run to make the return trip (all downhill) at an average speed for the entire round trip of six miles per hour?

This puzzle has already been done, except with cars, towns, and different speeds.

[Guest]

This was one of my favorites...

those who answered that it's impossible are correct. You can't average speed and distance. put an arbitrary distance to it and you realize you have used up all your time in the first half.

It was agreed upon in the forum that it is possible to do this if you detour

[Faizaan]

Well i guess...

You are screwed... and already out of time, too. You half to run the rest of the race in zero seconds. Even Superman can't go that fast. So unless your Super-Duper-Man...

Spoiler for UMMM...:

You're Screwed.

[Faizaan]

It was agreed upon in the forum that it is possible to do this if you detour

Hmm... but wouldn't that be cheating???

[bonanova]

if you run 3mph for 1 hour you run 3 miles

if you run 9mph for 1 hour you run 9 miles

3+9=12 miles @ 2 hours or 6mph

But here is the problem, if the first half is only 3 miles then the total lenght is 6 miles.

Averaging two speeds run for identical time intervals is ok. But ...

Read the OP.

1. There is no mention of 3 miles or 6 miles - it's 3 mph and 6 mph.
   
2. It's the distances that are identical.
   

Since this puzzle has appeared many times in this forum, it's locked.